NXT therapy improves the anti-apoptotic effects of D-HDL for HUVECs following TNF-α treatment. HUVECs were pre-incubated with N-HDL, D-HDL BL, D-HDL M3, D-As-HDL BL, D-As-HDL M3 in 100 mg/ml apolipoprotein A-I for 18 h. TNF-α was added to each well and incubated for 24 h. (A) Representative images of apoptotic cells stained by Hoechst 33258 (objective lens magnification, ×100). (B) The apoptotic cells were evaluated by counting 10 random fields. (C) Caspase-3 activity in cell lysates was determined. (n=6). *P<0.05, **P<0.01 (Student's t-test). NXT, naoxintong; HDL, high-density lipoprotein; HUVECs, human umbilical vein endothelial cells; TNF-α, tumor necrosis factor-α; N, normal; D, diabetic; BL, baseline; M3, 3 months of NXT; PBS, phosphate-buffered saline; As, atherosclerosis; ns, no significance.